Samsung 49" 6400 UHD

I bought a Samsung UE49KU6400

People ask me where I bought my TV. I got it at DID Electrical on Malahide Road for EUR699. I’m very happy with DID’s price and service; another store where I looked at this TV had it for EUR849. I got extended warranty for EUR99, but then I got a EUR20 voucher for another purchase (spent on an aerial) and an additional EUR20 discount at manager’s discretion. Very, very pleasant experience.

Some thoughts and discoveries on the TV:

  • Samsung UE49KU6400(pricespy) can do 4K and HDR. Not much content that can do it, but Netflix in Ireland has a few pieces of content: things like House of Cards are 4K, and Marco Polo is HDR.
  • Builtin Tizen OS is useless. Builtin Netflix app doesn’t say anything about supporting HDR, so I assume it doesn’t. I am very happy that I have nVidia SHIELD. Switching between TV and an app is harder and lossier than switching to external HDMI.
  • Builtin Vimeo app is semibroken, and Android TV version of Vimeo seemingly does not exist.
  • nVidia SHIELD can be used to send Marco Polo in HDR.
  • nVidia GPUs before Maxwell and Pascal architecture (e.g. my GTX 770) can’t output HDR.
  • Quite happy with upscaling. Frame interpolation, presumably up to 60fps, can be turned off but is a pretty nice parlor trick.
  • PIP only works when you have the TV tuner set up, and when you switch to an external input (e.g. HDMI). Switch to HDMI, and then you can watch TV in a small window. Useful only if you want to watch YouTube videos while ads play on TV.
  • Upscaling from full HD and below works fine with neat results.
  • Image can be made quite bright and exciting-looking. It looks like you’d want to switch to Dynamic image type to get the in-store experience. Probably bad for eyes though.
  • There’s sports mode. It makes image brighter. It’s got a dedicated button on the remote, which causes very annoying noise and animation to appear when sports mode is entered AND left.
  • There is a gaming mode, presumably cutting down on latency. I didn’t try to notice a difference.
  • There is a second remote called “Smart Remote”. There’s way less buttons than on the main remote. It tries to be similar to Apple TV or SHIELD remote. Rather useless.
  • To get HDR from HDMI, you have to turn on the relevant option (“UHD Color”). Not sure why that’s not the default.
  • 4K/UHD HDR is barely noticable, but nice.
  • It seems that “UHD Color” (HDR) is only available on one of the inputs. I’m not sure, but it didn’t look like it could be turned on on another HDMI input after I flipped it on on HDMI1. Not that I have another HDR-capable device; this involved re-plugging SHIELD into HDMI2.

Overall I’m happy.

Changing the default file manager away from Nautilus

Nautilus is opening the desktop, making the experience miserable under i3 when all you’re trying to do is ‘view files in directory’.

XFCE’s Thunar is lightweight, and it doesn’t try to create a desktop window.

To get apps such as Chrome to handle “open directory” commands using Thunar, teach xdg-mime about it:

$ sudo apt-get install thunar
$ xdg-mime query default inode/directory
nautilus.desktop
$ xdg-mime default Thunar.desktop inode/directory  # yep, Thunar's desktop file is titlecased on Debian-derived systems
$ xdg-mime query default inode/directory
Thunar.desktop
$ xdg-open .
...thunar opens...

This is sort-of a follow-up to my previous post on this topic. See also, Debian’s article about usage of MIME types.

But my dog does.

Migrating Prosody from text store and sqlite3 to PostgreSQL

Assumptions

  • You started off from the basic storage config:
    • Regular data is in filesystem.
    • mam (xep0313) message archive is in SQLite3.
  • You want to transition to using just PostgreSQL.
  • PostgreSQL version is 9.4.

Installation

# # largest version of pgsql you have
~# apt install postgresql-9.4-client

# # get lua-dbi module for pgsql
~# apt install lua-dbi-postgresql

Creating PostgreSQL user

# # PostgreSQL trusts users connecting over unix domain socket to be the
# # same as their local account.
# # Therefore, become postgres -- the admin account.
user:~$ sudo su postgres

# # run user creation
postgres:~$ createuser --interactive
# # name: prosody
# # no other administrative options

# # run postgresql client
postgres:~$ psql
-- create database
CREATE DATABASE prosody;

-- give the prosody user all rights on it
GRANT ALL ON DATABASE prosody TO prosody;

-- in case of connecting over network and using md5 trust,
-- set prosody account password:
ALTER ROLE prosody WITH ENCRYPTED PASSWORD 'here_some_password';

Over network?

Assuming you want to connect over the network, edit /etc/postgresql/9.4/main/pg_hba.conf. Append:

# type, database, user, address, auth method
host prosody prosody 172.16.0.0/16 md5
  • Try to minimize your permitted netmask.
  • Can you configure a more secure auth method than md5? Do so.

Migrate data from filesystem

# # as prosody local user

prosody:$ cd prosody-hg/tools/migrator

# # overwrite the config.
prosody:$ cat > migrator.cfg.lua << _EOF
local data_path = "../../data";

input {
        type = "prosody_files";
        path = data_path;
}
output {
        type = "prosody_sql";
        driver = "PostgreSQL";
        database = "prosody";
        username = "prosody";
        password = "here_some_password";
        host = "database.host.here"; -- this assumes network connection; migration with local user credentials was not attempted.
}
_EOF

# # run the migrator in ~/prosody-hg/tools/migrator
prosody:$ lua prosody-migrator.lua input output

Migrate mam archive from SQLite3

# # as prosody user

prosody:~$ cd prosody-hg/data

# # Having first verified there is nothing in Prosody table...
prosody:$ sqlite3 prosody.sqlite 'SELECT COUNT(*) FROM prosody;'
# # ...drop prosody table. All its data (roster etc) was until now stored on the filesystem.
prosody:$ sqlite3 prosody.sqlite 'DROP TABLE prosody;'

# # dump and massage the sqlite3 output, piping it into psql.
# # psql authenticates as the 'prosody' user and does not require the password.
prosody:$ sqlite3 prosody.sqlite .dump | \
    grep -v 'BEGIN TRANSACTION;' | \
    sed 's/PRAGMA foreign_keys=OFF;/BEGIN TRANSACTION; SET CONSTRAINTS ALL DEFERRED;/' | \
    grep -v sqlite_sequence | \
    awk '/CREATE TABLE/{gsub("`","\"");} 1' | \
    awk '/CREATE UNIQUE INDEX/{gsub("`","\"");} 1' | \
    sed 's/INTEGER PRIMARY KEY AUTOINCREMENT/SERIAL PRIMARY KEY/' | \
    psql

# # manual step 🙁
# # fix the autoincrement.
prosody:$ sqlite3 prosody.sqlite 'SELECT COUNT(*) FROM prosodyarchive;'
# # use this number + 1 in:
prosody:$ echo 'ALTER SEQUENCE prosodyarchive_sort_id_seq RESTART WITH 123456;' | psql

Update Prosody config

In prosody.cfg.lua:

storage = {
        archive2 = "sql";
}
sql = { driver = "PostgreSQL", database = "prosody", username = "prosody", password = "here_some_password", host = "database.host.here" }

Getting sound and other panels in gnome-control-center outside GNOME

Missing some panels in gnome-control-center? No “Online Accounts”? No “Sound”?

Apparently, panels are defined through .desktop files in /usr/share/applications (!), and they mostly have the setting of OnlyShowIn=GNOME; or OnlyShowIn=GNOME;Unity;.

To trigger them appearing in, say, i3, xfce or similar, you need to pretend you’re actually running GNOME by exporting the XDG_CURRENT_DESKTOP variable with the value of GNOME.

#!/bin/sh
XDG_CURRENT_DESKTOP=GNOME gnome-control-center

Vidalia crashing on Ubuntu 14.04 due to incorrect AppArmor profile

This has been going unfixed for years now.

For me, the fix involved adding the following into /etc/apparmor.d/usr.bin.vidalia.

/usr/share/glib-2.0/schemas/ r,
/usr/share/glib-2.0/schemas/** r,

Then, I reloaded AppArmor /etc/init.d/apparmor reload and the contraption worked. If you get asked about your Tor control password, restart tor /etc/init.d/tor restart.

Where Buddypress stores the custom username?

I’ve installed new WordPress. I renamed an existing user ivucica to an administrative name (let’s say goblin), then I created a new user ivucica. This was done low level, by typing in manual MySQL queries, manipulating the wp_users table.

Then I installed Buddypress. Buddypress thought goblin was named @ivucica, while ivucica got named @ivucica-2.

Looks like there is a column in wp_users named user_nicename which is used by Buddypress and where this is pulled from. It doesn’t match the user_login column.